# String latch

Process

Captures a string input value on a pulse and holds it internally. The captured value is sent to the output on trigger or optionally on capture.

String latch

String latch ver: 1

# Inputs

ID	Abbrev	Name	Type	Default	Description
`value`	`V`	Value	STRING		The string input value available for capture.
`capture`	`C`	Capture	BOOLEAN	`false`	Pulse input. Rising edge latches the current input value internally. If 'Trigger on capture' is enabled, also sends the value to the output.
`trigger`	`T`	Trigger	BOOLEAN	`false`	Pulse input. Rising edge sends the captured value to the output, even if the output already holds the same value.
`reset`	`R`	Reset	BOOLEAN	`false`	Pulse input. Rising edge resets the output and captured value to the configured default value. Dominant input.

# Outputs

ID	Abbrev	Name	Type	Default	Description
`value`	`V`	Value	STRING		The latched string value. Updated on trigger, on capture when auto-trigger is enabled, or on reset.

# Configuration

ID	Name	Type	Default	Unit	Description
`default_value`	Default value	STRING			The value restored to the output and captured state on reset. Details: Required
`trigger_on_capture`	Trigger on capture	BOOLEAN	`true`		When enabled, capturing a value also immediately sends it to the output. When disabled, capture only stores the value internally until an explicit trigger.

# State

ID	Name	Type	Default	Description
`captured_value`	Captured value	STRING		Holds the internally captured string value.
`prev_capture`	Previous capture state	BOOLEAN	`false`	Stores the previous state of the capture input to detect rising edges.
`prev_trigger`	Previous trigger state	BOOLEAN	`false`	Stores the previous state of the trigger input to detect rising edges.
`prev_reset`	Previous reset state	BOOLEAN	`false`	Stores the previous state of the reset input to detect rising edges.

# Source Code

View Volang source

channel = input::channel()
value = input::value()

// Handle "reset" input first (dominant input)
if (channel == "reset") {
    prev_reset = state::get("prev_reset")

    if (value and !prev_reset) {
        // Rising edge on reset - restore default value
        default_value = config::get("default_value")
        state::set("captured_value", default_value)
        output::set("value", default_value)
    }

    state::set("prev_reset", value)
    return
}

// Handle "trigger" input
if (channel == "trigger") {
    prev_trigger = state::get("prev_trigger")

    if (value and !prev_trigger) {
        // Rising edge on trigger - send captured value to output
        output::set("value", state::get("captured_value"))
    }

    state::set("prev_trigger", value)
    return
}

// Handle "capture" input
if (channel == "capture") {
    prev_capture = state::get("prev_capture")

    if (value and !prev_capture) {
        // Rising edge on capture - latch current input value internally
        captured = input::get("value")
        state::set("captured_value", captured)

        // Optionally send to output immediately
        if (config::get("trigger_on_capture")) {
            output::set("value", captured)
        }
    }

    state::set("prev_capture", value)
    return
}

// "value" input changes are ignored - output holds until next capture, trigger, or reset